The present invention relates generally to devices used in the diagnosis of anomalies in teeth and, more specifically, to dental burs used in penetrating the surface of teeth to facilitate the diagnosis by a practitioner.
Incipient initial carious lesions in dentin beneath enamel pits and fissures of teeth often can be very difficult to diagnose, even with good visual access and with the use of an explorer tool having a sharp pointed tip. The difficulty in diagnosis is present even with excellent radiographs. In teeth with deep pits and fissures, dentinal caries can develop at the dentinoenamal junction and progress further into dentin with minimal or no clinically-evident signs of disease in the overlying enamel. This phenomena in the art is referred by the term "hidden caries".
One non-treatment modality of dealing with this problem is the "watch and wait" process and in the event that cavitation occurred, a diagnosis is made via a visual inspection and explorers and radiographs. At this stage the lesion is more advanced and requires a less conservative treatment to treat the lesion.
A preemptive aggressive treatment resulting in a classical amalgam restoration for what is believed to be an incipient carious lesion in the dentin between enamel pits and fissures results in a significant removal of tooth because amalgam restorations require a minimum of approximately one and one-half millimeters in depth to establish the proper holding characteristics for the amalgam restoration.
With the advent of the widespread exposure of patients to topical fluorides, the difficulty in identifying incipient carious lesions has been exacerbated. This occurs because the fluoride makes the enamel immediately adjacent to pits and fissures relatively resistant to carious lesions, while not affecting the dentin. Thus, the dentin caries can develop at the dentinoenamal junction and progress further into dentin with minimal or no clinically evident signs in the overlying enamel.
Minimally invasive techniques for diagnosing initial carious lesions have included the use of small ball-shaped round diamond or carbide burs having a diameter of approximately 0.25 millimeters to 1 millimeter. The problem with using such round diamond burs is that they do not leave the examined area with a smooth surface rendering further examination by the practitioner using an explorer device difficult to assess the existence of carious lesions. Another problem with the small round diamond bur is that it does not lend itself to plunge cutting for the examination of carious lesions deep in dentin beneath the tooth enamel. The short length of such conventional round diamond burs often does not provide sufficient depth for cutting of the tooth enamel. Furthermore, round burs do not cut smooth, flat, axial walls and leave unsupported enamel rods. Moreover, when inserting a typical round diamond bur into a tooth, the wide cutting portion at the diameter of the round bur often disadvantageously removes more of the patient's tooth than is required for certain dental procedures.
Another approach to investigating insidious carious lesions is the use of an air abrasion tool. Disadvantageously, treatment with the air abrasion tool is costly because it requires a large investment of capital for the air abrasion equipment. Furthermore, the air abrasion tool is not easy to control and creates a significant amount of debris in the dental work area, particularly when examining relatively large caries in a tooth. Moreover, air abrasion requires a significant learning process to learn a proper preparation technique.
The present invention is directed to overcoming, or at least reducing the problems set forth above.